Friday, 1 April 2016

Absolute Power

I recently wrote about our experiences at SSI 2016. We set up our room with my own PS Audio DirectStream DAC, a PS Audio P10 Power Plant, and the recently-introduced and highly-regarded PS Audio BHK 300 Signature mono block power amplifiers. Loudspeakers were the Sopra No 2 from Focal, and a wide array of cables, cords, and interconnects from AudioQuest. The BHK 300 monoblocks in particular caught my attention, so much so that I took them home with me. If they were able to deliver the captivating performance I heard at the show in my own listening room, then I was willing to consider purchasing them for our reference system.

The Focals were returned directly to Coup de Foudre, the dealer which had kindly lent them to us for the show, but the PS Audio gear and the AudioQuest cables came home with me, where I could pack them and ship them back at my leisure. The BHK monoblocks and the P10 Power Plant both share the same purposeful-looking chassis, and weigh in at a little over 80lb each - not unusual for high-end audio gear these days (my Classé CA-2300 is about the same size and weight) - but each one requires two people to manhandle it into place. The P10 went down to the basement to be packed ready for shipping, but the monoblocks were taken directly to the listening room.

I sat the two monoblocks directly on the floor, either side of the incumbent Classé. Since I had dismantled my equipment rack to use at SSI as well, I decided not to re-assemble it just yet because I use bi-wired runs of Cardas Golden Cross speaker cable. Heavy duty speaker cable makes the already awkward process of swapping amplifiers doubly difficult if one of them is ensconced in an equipment rack. Better to leave everything open and accessible on the floor for the time being.

Two years ago I spent the summer trialling a set of über-expensive cables from Transparent Audio. While there was no doubt that these cables had opened up vistas of clarity, smoothness of delivery, and airy sound staging, their benefits appeared to come at the expense of what I term a “breathless” quality to the sound, and I ultimately decided not to purchase them. I find it hard to describe this “breathless” quality. It’s as though reproducing the music is hard work and leaves the equipment panting for breath. The dynamic quality I expect from crystal clear sound just wasn’t there. Peaks seem to be - not ‘muffled’ or even ‘veiled’ per se - but somehow lacking a realistic sense of dynamic impact. I felt a constant need to crank up the volume just a notch, then another notch, then another. It was as though the musicians were just mailing in their performances. Like I said, hard to describe, but it left me feeling short of breath. I sent the cables back.

Imagine my astonishment when I fired up the BHK monoblocks and heard what amounted to the same “breathless” sound quality. A slightly better “breathless” quality, with a smoother midrange, a more detailed and deeper soundstage, and some of the tantalizingly accurate instrumental textures that I had heard from them at SSI, but that very distinctive “breathlessness” was back for all to hear. Back to the Classé again just to be sure that something wasn’t wrong with the rest of the system - there wasn’t - and once more to the BHK 300s. Still the same. It didn’t seem likely, but I left it to play for a day or so in case some sort of break-in process was under way.

Further break-in was not clearing up the problem. Had I misheard the qualities I thought I was hearing at SSI? Or were they actually down to the Focal speakers more than the BHK 300s? Neither of these seemed too plausible to me, although I wasn’t about to discount them entirely. I decided I would try to recreate the SSI setup as much as possible, but using my B&W 802 Diamonds in place of the Focals. Unfortunately, the AudioQuest cables were all neatly packed away and ready to ship, and it was going to be a nuisance to get them all out again. But the PS Audio P10 Power Plant was still unpacked and sitting nearby. So the first thing I tried was putting the P10 into the circuit, with the BHK 300 monoblocks and the DirectStream DAC both plugged into it.

Powered everything back up again and … &%$#@#@*&%???!! What did I just hear? The sound was utterly transformed. This was a perfect recreation of all the qualities I had heard at the show. The “breathless” quality had completely vanished. Disappeared as if by magic. The widely-lauded qualities of the BHK 300s now shone through in spades. The deep, wide, and tactile soundstage. The tube-like tonal purity of the midrange, the accuracy, presence, and sheer believability of individual instruments and voices, all these things were suddenly there in spades.

How to make sense of this? Was I hearing a specific synergy between the BHK 300 monoblocks and the P10 Power Plant, and if so, what was I supposed to make of it? I knew the obvious thing to do was to swap out the monoblocks once more for the Classé CA-2300, this time with the P10 Power Plant in circuit, but I was too busy queuing up a whole bunch of favourite albums and tracks to hear how they sounded in this newly-amazing system. Eventually, though, I did get round to it.

The PS Audio P10 Power Plant utterly transformed my CA-2300 amplifier. About 75% of the improvements I was hearing from the BHK 300 monoblocks were now being delivered by the Classé. The greater ease in dynamics. The tighter imaging and deeper soundstaging. The improved sense of presence and palpability. It has made me seriously re-assess the CA-2300.

I had in the past tried a couple of high-end power conditioners from MIT and Transparent Audio and found that their contribution to the sound had been marginal at best. I concluded that this was due to the fact that I live in the country and have generally clean, good quality mains power. I was not expecting the P10 Power Plant to deliver anything very different. In my listening room, for example, AC power cords tend to have a less obvious impact on the sound than they do in most other setups. And yet the P10 Power Plant didn’t just make a difference. It utterly transformed the sound to the extent that I am concerned it will never be possible to go back to how it was before.

For sure my auditioning session with the BHK 300 monoblocks is now an order of magnitude more challenging. It is still early days here, but if you asked me to choose between the Classé CA-2300 with the P10 and the BHK 300s without it, my feeling is that the P10/CA-2300 combo might win out. The P10 is that good, and that important. On the other hand, when plugged into the P10 the BHK 300 monoblocks wipe the floor with anything else I’ve ever spent quality time with. If money wasn’t an issue, the solution would be trivial.

The P10 has a couple of other tricks up its sleeve. Its touch-screen front panel gives the immediate impression of being the sort of gimmick that manufacturers feel the need to add to expensive high-end products to help justify the price, but just a little experimentation with the P10 proves the opposite.

First of all, the P10 has a ’Scope mode which turns the display into an oscilloscope showing a real-time rendering of the actual input mains voltage waveform. This is very interesting, because the peaks of the waveform show distinct distortions ranging from a flattened top to the appearance of various spikes. These are caused by the fact that the amplifiers draw most of their mains current during the peaks of the voltage waveform and little to none at any other time. A further touch on the screen and now the display changes to the waveform of the actual output voltage delivered to the attached equipment. This comes up as being a clean and very pure sinusoid. A third touch shows the difference signal between the two. This is in effect the cumulative distortion which is being removed by the P10. Well golly gee.

A third touch and we get a screen showing a summary of the P10’s instantaneous performance, including input and output voltage levels, THD levels, and power draw. Interestingly, the reading I get shows an input THD of only 2.2%, which is quite low and is consistent with my notion that I have reasonably clean mains power. The output THD is shown as being 0.2%. That such a small numerical difference can account for such a dramatic improvement in sound quality is not something I would have expected, but I’m sure that’s far from being the whole story.

Also on the P10’s display is a setting which toggles between pure sine wave output and a ‘multi-wave’ output. The idea behind ‘multi-wave’ is that it adds an element of third harmonic distortion to the P10’s mains output voltage waveform. Such distortion has the effect of increasing the percentage of time that the waveform spends in the vicinity of its voltage peak, and therefore increases the percentage of time during which your amplifiers’ power supplies can draw current from the mains. This is said to convey a benefit equivalent to increasing the amount of capacitance in the amplifier’s power supply. The amount of added ‘multi-wave’ can be set on a scale from 1-6. For my early listening I am using the pure sine wave setting, and am not noticing any significant change with the multi-wave setting. But you can imagine that this type of response would be very much device-dependent.

The P10 has an interesting “clean” option, which adds a spectrum of decaying high frequencies to the output voltage waveform for a period of 5, 10, or 60 seconds (user’s choice). This is said to de-Gauss the input transformers in the power supplies of any connected equipment. According to Paul McGowan the effect lasts for something in the order of 20-30 minutes. I have to say that the effect of the “clean” option is surprisingly strong. After applying a 10-second burst of “clean” an extra layer of image depth was readily apparent, with more ‘air’ around the soundstage of individual instruments located deep in the soundstage. There was more ‘blackness’ to the background. I must note that this effect is something that cannot be dialled back out again, and so one must rely on a series of one-off A-B comparisons (as opposed to A-B-A-B) in order to assess it. But after performing a handful of those comparisons I am convinced that the effect is real, and is not at all subtle. Having said that, if the effect truly lasts for only 20-30 minutes then one must ponder its ultimate value. But ponder it I will.

There areother capabilities of the P10 that I have not yet explored. It can be connected to your home network via ethernet, where you can access additional features, mainly of the command/control/setup nature. It has a remote control which I have not used in anger [I already have a similar remote control for my DirectStream, and remote controls are like wives - one is a blessing but juggling two or more can be problematic]. The User Manual says the P10 can benefit from being mounted on after-market anti-vibration supports, but I have yet to try that - I don’t believe I have anything to hand that will hold 80lb!

So there you have it. The PS Audio P10 Power Plant has made a bigger difference, rendered a larger improvement, than any single component change I have EVER made to my reference system, and probably bigger than any I ever will. It is seriously expensive, no doubt about that. But so are the BHK 300 monoblock amplifiers. And I would go so far as to say - and Paul McGowan is going to de-friend me for this - that the BHK 300’s might just represent $15,000 wasted if you’re not going to power them from a P10 Power Plant (although, realistically, the same probably applies to every other $15,000+ power amplifier out there). The combination, however, is out of this world, and I will write about it separately if I can learn to live with them and without my life savings.